ey went on, places of this kind were met with;
while twice over they had to pause at spots where the water must have
sprung from a shelf ten or a dozen feet down into a basin which it had
hollowed for itself in the course of time.

Upon the first of these sudden drops presenting itself Mike stopped with
the lanthorn.

"Here's the end of it," he said. "Goes down into a sort of bottomless
pit, black as ink. Let's go back."

Vince stepped close to his side and gazed down into the black depths
with a feeling of awe, the place looking the more terrible from the fact
that the tunnel had narrowed until there was only just room for them to
stand between the smooth granite walls.

"Looks rather horrid," said Vince. "Worse than a big well. Let's see
how deep it is."

He stepped back and picked up a stone that had fallen from the roof,
returning to where Mike held up the lanthorn for him to see.

Down went the block of stone, and they prepared themselves to hear it go
bounding and echoing far away in the bowels of the earth; but it stopped
instantly with a loud clang, and Vince cried,--

"Why, it isn't deep at all! I can see it."

A ring or two of the rope was cast loose, passed through the handle of
the lanthorn, and upon lowering it down block after block presented
itself sufficient to enable them to descend into what proved to be quite
a hollow, from which the stream must have leapt into another and again
into another, each being a fall of only a few feet. After which there
was another great pot-hole, like a vast mortar with a handleless pestle
of rock remaining therein.

Beyond this the water had carved out a rugged trough, steep enough to
form a slide if they had felt disposed to trust themselves to it, and
Vince laughingly suggested that they should glide down.

"Only it wouldn't do," he added. "We can't tell what's at the bottom.
Might mean a bad fall. Had enough of it?"

"Yes, ever since we started," replied Mike.

"Then you want to go back?"

"Oh no, I don't," retorted Mike. "One can't help feeling that one must
keep on and see where it goes to, even if it does make you turn creepy.
Doesn't it you?"

"Well, yes, I suppose so," replied Vince thoughtfully; "and I wouldn't
go on, only it's so easy to climb back, and the air feels fresh and
sweet, so that except that it's dark there's nothing to mind."

"But suppose the candle went out. How much is there left?"

As Mike spoke, he opened the door